Fuse



A. GRIEVE FUSE Filed May s. 1921 ,L/Wd/ Patented Dec. 2, 1924.

`UNITED STATES ARCHIBALD GRIEVE, OF WESTPORT, CONNECTICUT, ASSIGNOR T0 CHARLES E. KEMPER,

PATENT OFFICE.

INC., OF WESTPORT, CONNECTICUT, A CORPORATION OF CONNECTICUT.

FUSE.

Application filed May 5, 1921.

To all whom it mcag/ concern.'

Be it known that. I, AnoHiBALD Ginnvn, a subject of the King of Great Britain, residing at lest-port, in the county of Fairield and State of lConnecticut, have invented certain new and` useful Improvements in Fuses, of which the following is a. specification.

My invention relates to electric fuses, and particularly to a renewable cartridge fuse of the clip type. Specilically, my invention relates to a detailed improvement in the construction shown in my co-pending application Serial No. 442,516, filed February 4, 1921, and is embodied in several forms in the accompanying` drawings, in which Fig. 1 is a broken longitudinal elevation of a cartridge fuse;

Fig. 2 is a side elevation of the washer or button illustrated in Fig. 1;

Fig. 3 is a plan ot the but-ton sho-wn in Fig. 2;

Fig. 4 is a partial longitudinal section through a modified construction;

Fig. 5 is an end view of the ferrule shown in Fig. at; and

Fig. 6 is a longitudinal section through an end ferrule and button, illustrating a rfurther modification.

In the construction shown in my prior application above mentioned, the end cloisure for the fuse casing comprises a bushing secured at the end ot the casing, a ferrule screwing on the bushing and a washer within the errule, the washer to establish contact with the fuse strip and to deflect 'the gases and cause them to travel an eX- tended path before escape. In that construction the washer is loosely connected to the end diaphragm of the errule. On the escape of the gases, following a. rupture of Athe fuse strip, metal is apt to be deposited Serial N'O. 467,027.

position at 12 and provided with serrations 13 in its neck area which not only assist in maintaining the joint between the casing and the bushing, but also preventing the escape of gases at this point on blowing ot' the fuse. The bushing is externallv threaded at 14 to receive the screw terrule 15. A shutter 16 such as shown in Keeter Patent No. 1,491,704, April 22, 1924. pivoted on the bushing serves to substantially close the end opening 17 in the latter through which the end 19 of the fuse 18 passes, and is angled ove-r the outer face of the shutter. Resting upon the fuse end and establishing contact therewith is the washer or button 20, provided on its inner face with a contacting boss 21.

In 'the construction shown in Figs. 1, 2 and 3, the periphery of the button is threaded to engage the threads of the ferrule 15. Marginal slots 22 intersecting the threads afford vent passages through which the gases from the fuse chamber pass. These passages open to a restricted Vannular chamber allorded between the outer face of the button and the end diaphragm of the 'errule by a shoulder 23 formed in the outer face of the button. The central boss 24 on the outer face of the button projects into or through the central end ope-ning 25 in the tei-rule, and the gases are led to the opening 25 by the venting cross slot 2G cut in the outer Jface of the button. This venting cross slot is preferably arranged at right angles to the slots 22, thus forcing the gases not only to change direction but also to travel andv extended path in contact with heat absorbing surfaces bvefore escaping at the opening 25.

It is obvious that when the fuseis blown and the ferrule 15 has been removed to permita new link 1S to be inserted, the button 2O may be screwed out from the fer rule by means of a screw-driver inserted in the slot 26 and passing through the opening 25. Any metal deposits in the venting passages may then be readily broken or scraped away to leave the latter in proper condition for a suceeding operation of the fuse.

A further feature of advantage in this construction resides in the fact that after the errule 15 has been screwed down on the bushing, the contact between the button 2() and the bent-over end 19 of the fuse strip may be made more perfect by slightly lscrewing-iin the button 20. This has the cil'ect also ot locking the cap against accidental unscrewing on the bushing ll incident to vibration ot the fuse support.

In the construction shown in Figs. 4 and 5, the end diaphragm of the terrule 2T is provided with internal ribs 28 by means ot' a punch which indents the diaphragm at several points 29. These ribs 528 space the washer 8() slightly trom the end dia]')hragm ot the terrule and thus afford a` passage leadingl to the vent openiiig 3l. The washer l() rests t'reely within the cap and is provided with a peripheral thread which sufiiciently closel)Y approaches the wall of the Vterrule 2T to compel the gases to Jr'ollow a circuitous path through the thread channels to the venting space 252 betweeny the outer tace ot the button and the diaphragm. ot 'the tcrrule. Then the terrule is removed vtor the renewal ot the tuse strip. the washer 3() may be readily t'orced out by means ot a screw-driver inserted through the vent hole S1.. and any obstructing deposits may be readily removed.

In Fig. I have shown a still further n'ioditication in` which the button 33 has its outer boss Jc threaded to engage the tapped end vent hole in the terrule Vent channels 3G may be formed either in the boss 34k or in the hole 35 to permit the gases to escape, and the periphery ot the washer may be plain, as in my applica-tion above identilied, or may be provided with a peripl'ieral thread to compel the gases to follow a circuitous path. This construction has an advantage over that shown in Fig. 'l in that there is little or no deposit trom the gases on the threads of boss 34 since they escape 'freely at the passages 36. In the construetion shown in Fig. l, the gases tend to tollovv the peripheral. threads ot the button and form a deposit which seals the button in position so that its removal is at times a difficult matter. This modified construction has the advantage, set forth in my application above identified, ot' maintaining the button as part ot the terrule unit, while nevertheless permitting the washer to be removed `to clean the vent passages.

The specilic details ot construction indicated may be variously modified while retaining the advantages ot what I claim as my invention.

l. A cartridge tase having a detachable terrule with end closure diaphragm aperranged within said terrule and having on its outer tacc a boss threaded to screw in Isaid tapped hole and shaped to partially obstruct the latter.

:3. A cartridge 'tuse having ay detachable terrule with end closure diaphragm aperturcd on the axis ot' the tel-rule to aii'ord a vent` a button arranged within said terrule and obstructing direct escape ot Jrom the tuse chamber to the vent in said diaphragm. and a threaded connection between said terrule and button to permit the latter to be detached trom the ferrule said button having on its outer tace a bossl partially obstructing the vent aperture in the end closure diaphragm ot the ferrule.

l. A cartridge tuse having an end closure unit comprising a screw terrule with vented end closure diaphragm and detachably connected gas-tiletlecting washer arranged within said t'errule and having a boss which enters and partially obstructs said vent aperture.

A cartridge Vtuse having an end bushing. a terrule having a` screw connection therewithl` and a lock washer having a threaded connection with the terrule.

(i. cartridge tuse having a terrule with end closure dialihragm, a `tuse contacting button within the terrule and having a screw connection therewith, and an end openingl in the iterrule diaphragm to accommodate a button-removing tool.

T. Y cartridge 'tuse having a detachable terrule with end closure diaphragm provided with a central tapped hole, in combination with a gas-detlecting button arranged withiu said terrule and having on its outer Jface a boss threaded to screw in said tapped hole. said boss having a vent passage opening through its threaded area.

In testimony whereof I. have signed my name to this specification.

ARCHIBALD GRIEVF. 

